Re: [PATCH] input/touchscreen: Fix a missing check on regmap_bulk_read

[Dmitry Torokhov]

Hi,

On Mon, Dec 24, 2018 at 12:37:19PM -0600, Aditya Pakki wrote:
> regmap_bulk_read() can return a non zero value on failure. The fix
> checks if the function call succeeded before calling mod_timer.
> 
> Signed-off-by: Aditya Pakki <pakki...@umn.edu>
> ---
>  drivers/input/touchscreen/ad7879.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/ad7879.c 
> b/drivers/input/touchscreen/ad7879.c
> index 6bad23ee47a1..735cb4c0d913 100644
> --- a/drivers/input/touchscreen/ad7879.c
> +++ b/drivers/input/touchscreen/ad7879.c
> @@ -247,11 +247,12 @@ static void ad7879_timer(struct timer_list *t)
>  static irqreturn_t ad7879_irq(int irq, void *handle)
>  {
>       struct ad7879 *ts = handle;
> +     int ret;
>  
> -     regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS,
> -                      ts->conversion_data, AD7879_NR_SENSE);
> +     ret = regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS,
> +                             ts->conversion_data, AD7879_NR_SENSE);

I'd probably say:

        error = regmap_bulk_read(...);
        if (error)
                dev_err_ratelimited(...);
        else if (!ad7879_report(ts))
                mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);

Were the failures observed in real life or it is some kind of class
project?

>  
> -     if (!ad7879_report(ts))
> +     if (!ret && !ad7879_report(ts))
>               mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
>  
>       return IRQ_HANDLED;
> -- 
> 2.17.1
> 

Thanks.

-- 
Dmitry